On March 8, 2014 Malaysian Airlines flight 370 left Kuala Lumpur, headed for Beijing. Less than an hour after takeoff it deviated from its flight path, flying in a southwesterly direction until it eventually plunged 239 people into a remote swath of the Indian Ocean.

Now, just over four years later, the overwhelming consensus from experts is that the disaster was no accident. Because as air crash investigator Larry Vance summarizes: “the disappearance of MH370 was a man-made event.”

The Australian TV show 60 Minutes was responsible for bringing together five experts from around the world to discuss their learnings on Sunday night. While they disagreed on certain points, all five thought the most likely scenario was that Malaysian Airlines pilot, Captain Zaharie Ahmad Shah, flew the plane deliberately off course and ditched into the ocean.

First, they point to the way that the plane’s communications systems were manually cut before the plane quietly traversed Thai and Malaysian airspace, heading south. There was no communication with any air traffic controllers in the hours after, and no emergency distress calls.

A particularly affecting piece of evidence came from senior pilot and instructor Simon Hardy, who noted that MH370 had made an odd detour over the Malaysian region of Penang, which happens to be the pilot’s homestate. In the same way that pilots will dip their wing over famous landmarks to give passengers a better look, Hardy believes that Captain Zaharie Ahmad Shah wanted to wish his childhood home one final goodbye.

For air crash investigator Larry Vance, the most damning piece of evidence washed up on the Indian Ocean island of Réunion in 2015. This was the infamous “flaperon,” which is a movable part of the wing controlling the plane’s roll and bank. Surprisingly for Vance, the flaperon was found almost completely intact, indicating that the plane had hit the water slowly and in a controlled landing.

In an article published in Tuesday’s the Australian, Vance explained that in previous crash investigations, planes that crash into water are usually reduced to tiny fragments. “When Swissair 111 hit the ocean at high speed off Nova Scotia, it exploded due to the hydrodynamic pressure of impacting with the water and came apart into some two million pieces,” Vance wrote. “In the case of MH370, essentially, the ­entire right-wing flaperon was ­recovered… there should have remained little doubt that a pilot was controlling MH370 at the end of its flight.”

As Vance suggested on 60 Minutes, his article, and upcoming book, all this suggests that Captain Zaharie Ahmad Shah deliberately depressurized the plane, knocking all passengers and staff unconscious, and then piloted the plane on a suicide mission to a predetermined remote location where he knew there was little chance the plane would be found.

This is despite the fact that intense scrutiny of Captain Shah’s home life and medical records have failed to show any evidence of mental illness. There was however a flight simulator found at his home, with a deleted file that included a practice run over the Indian Ocean.

“The simplicity of the disappearance of MH370 comes down to this: either it was a criminal act or it was not,” writes Vance. “The evidence confirms it was a criminal act, committed by one ­individual who, as a pilot in the airplane, had a simple means to carry it out.”